Our findings are experimentally consequential for probing HOT insulators, apart from the crystalline systems,
also in metamaterials. The paradigmatic model of the 2D second-order topological insulator, the Benalcazar-Bernevig-Hughes (BBH) model [1]}, equivalent to the minimal lattice model in Eq. (REF ) [2]}, has been realized in the lattice of microwave resonators [3]}. A dislocation defect in this setup should be created by a local hopping modification through \(\pi \)  phase factors across a line of missing sites ending at the dislocation center, analogously to the case of a translationally-active first-order topological insulator [4]}, and a disclination [5]}. In the BBH photonic lattice, where the sign of the hopping also can be locally manipulated [6]}, it should be therefore possible to introduce the dislocation defects and observe the defect modes, as in a first-order 2D topological photonic crystals [7]}, [8]}, and for a disclination defect [9]}. Finally, the artificial lattices can host HOT phases, as recently shown for Kagome lattice [10]}. Since both the amplitude and signs of the hoppings are controllable there, the dislocation defects should be possible to engineer, and therefore our theoretical predictions can be directly tested in these platforms.
